Methods for reducing power consumption in wait mode are known in the art. U.S. Pat. No. 4,961,073, to Drapac et al., teaches a method which operates in a communication protocol, having a paging transmission which includes two parts. While receiving the first part of the paging transmission, its validation is detected. If the first part is determined valid, then, the second part of the paging transmission is received. Otherwise, the power is disconnected from the receiver.
U.S. Pat. No. 5,537,100, to Hallberg, describes a method and device for use in pagers, which decodes a conventional serial paging transmission, using a methodology of looking for a pattern of non-correlated bits. The method according to this patent compares a received word with the address of the receiver of the pager and counts non-correlated bits between them.
For example, in a communication protocol having a Bose-Chaudhuri-Hocquenghen (BCH) decoder which is able to correct up to two errors, if at least three non-correlated bits are detected, then the received word is determined not relevant and the device disables power to the receiver, thereby reducing power consumption.
Reference is now made to FIG. 1 which is a schematic illustration of code collation, known in the art. Bit sequence 100 is the mobile station identifier (MSI) number of a receiver and bit sequence 102 is a received string of bits which is attached to a paging transmission. Sequence 102 includes an ID section 104 and a channel coding section 106, used for error correction. A BCH decoder, can correct up to one error in section 104, using section 106.
In the present example, there are two mismatches 110 and 112, between the received ID sequence and the MSI of the receiver. According to the prior art, if the number of mismatches is greater than the number of errors which can be corrected then, the received ID can be ignored. The reason being that even if the maximal number of errors in the received ID will be corrected using channel coding bits 106, there would still be at least one mismatch between the received ID and the MSI.
It will be appreciated by those skilled in the art that the above methods provide solutions for sequential data. Non sequential data can not be processed according to these methods. It will also be appreciated that in the art, there are no solutions to a situation when either the data or the channel coding bits are provided in a non-sequential format.